Abstract: A heater includes a heating element made of a PTC thermistor, electrodes formed on upper and lower surfaces of the heating element, flat metallic terminals connected to the electrodes, lead wires connected to inner surfaces of the metallic terminals that face each other, and an insulating case for covering exposed portions of the heating element, electrodes, and of the metallic terminals, and the connections between the lead wires and the metallic terminals. With this structure, since no bumps are produced on the outer surfaces of the metallic terminals by connecting the lead wires to the metallic terminals, the thickness of the insulating case over the metallic terminals is reduced. This allows a reduction in the thickness of the heater and an improved heat transfer between the heating element and the heated object.

Abstract: An acoustic-emission sensor includes a composite synthetic resin-ceramic piezoelectric element which has a plurality of substantially mutually parallel columnar ceramic piezoelectric bodies. The columnar ceramic piezoelectric bodies are polarized in a longitudinal direction and are disposed in a synthetic-resin matrix. Since only longitudinal waves can be detected from among acoustic-emission waves, an intensity and variation in intensity can be detected accurately.